Arrays of full wave dipole radiating elements have been observed to suffer from squint at high electrical down tilt angles. The term “squint” means the amount that a beam peak (midpoint between −3 dB angles) deviates from boresight of the antenna. See, for example, FIG. 9, which illustrates an azimuth beam pattern having approximately 12° of squint. A “full wave” dipole radiating element is a type of dipole that is designed such that its second resonant frequency is in the desired frequency band. In this type of dipole, the dipole arms are dimensioned such that the two dipole arms together span about three-quarters to one full wavelength of the desired operational frequency band. This is in contrast to “half-wave” dipoles, where the dipole arms are about one quarter wavelength of the operating band, and the two dipole arms together have a length of about one half the wavelength of the operating band.
While full wave dipoles have certain advantages in low band arrays of radiating elements in a multi-band array, known arrays of full wave dipoles typically experience disadvantageous coupling between two adjacent −45 degree polarization dipoles and +45 degree polarization dipoles, which may cause cross polarization and squint degradation at certain frequencies (referred to herein as “squint resonance frequency”). This effect particularly happens for the vertical polarization component of a slant dual-polarized dipole.
What is needed is an array of full wave dipole radiating elements with improved squint performance.